The insulators used in high voltage installations are prone to deterioration, particularly when exposed to harsh environmental conditions, such as strong sunlight and heat, for prolonged periods. Further, dust and other material accumulated on the insulation surfaces may provide a current path, leading to insulation breakdown. Proper preventative maintenance requires that the insulation be inspected regularly. New techniques of insulation condition monitoring require sampling of the insulator surface for laboratory analysis.
For obvious safety reasons, the high voltage power lines must be de-energised while such sampling or other contact occurs. Such power outages are not only inconvenient for electricity consumers, but also disruptive to the normal operation of power transmission systems.
It is an object of the present invention to provide apparatus and method for obtaining small samples of insulating material from high voltage installations under live line conditions.